1. Field of the Invention
The teachings in accordance with exemplary and non-limiting embodiments of this disclosure relate generally to a screw joint coupling structure of an intelligent stepping motor.
2. Description of Related Art
Concomitant with recent increased interest in vehicle safety, various head lamp control devices have been proposed configured to adjust an illumination angle of a vehicle head lamp, whereby illumination of direction to which a driver turns can be further increased when the driver drives a vehicle in the night.
In general, an angle adjustment device using a motor operation is used to change an angle of a head lamp on a vehicle, where a distal end of a motor is provided with a lead screw joint for joint connection to adjust an illumination direction of the head lamp by moving an angle adjustment unit.
A distal end of the lead screw installed at the distal end of the motor is fixed by a ball-shaped joint member using a spring pin. That is, the lead screw is formed with a first pin hole, and a second pin hole is formed at a coupling position of the ball-shaped joint member to allow the spring pin to be press-fitted into the first and second pin holes, and the ball-shaped joint member is fixed by being heat sealed.
However, the coupling structure thus described suffers from a disadvantage in that operation efficiency decreases due to a 2-step assembly process of a heat sealing process and a spring pin press-fitting process for coupling the frequently operating ball-shaped joint member to a screw joint. Another disadvantage is that a frequent movement may be generated at the coupling area to prevent a reciprocal feeding operation of the lead screw from being accurately realized, in a case a fine gap is formed at a spring pin press-fitting area.